Today Essential Question and Activities: Today Essential Question and Activities: Review Yesterday’s Lesson Essential Question: What are the different layers and functions of skin.

LEQ: How is the Integumentary system imperative in maintaining homeostasis?

Warm up: 1.What does the Integumentary system contain? 2.Where is melanin found and give one characteristic you learned yesterday about melanocytes? 3.Why are sebaceous glands always found near the hair? 4.Hand in Tree Man Homework

LEQ: How is the Integumentary system imperative in maintaining homeostasis?

ACTIVITIES: Graphic Organizer, Build the Skin, Lost in the desert.

1. Complete the Graphic organizer. Once finished bring it up to me to be checked off.

2. When your partner is done too- make a list of the supplies for the lab and for each supply come up with an educated guess about what part of the skin it could correlate to and WHY.

3. Have me check that off when finished and I will give you the lab instructions and materials.

4. Once you have constructed your skin bring it up to show me, finish ALL questions and hand in.

Today Essential Question and Activities: Today Essential Question and Activities:

Integumentary systemIntegumentary systemThe skin and accessory organs (Hair, membranes, glands, etc)

Epithelium MembranesEpithelium Membranes

Epithelial and connective tissues make up the different membranes of the human body.

Epithelium membranes ◦Are thin, sheetlike◦Are Composed of epithelium & underlying

connective tissue◦Cover body surfaces◦Line cavities◦There are four major types: serous, mucous,

synovial, and cutaneous

MembranesMembranesSerous membranesSerous membranes: Line body cavities that lack openings to the outside.

are a smooth membrane consisting of a thin layer of epidermal cells

They line and enclose several body cavities, where they secrete a lubricating fluid (serous fluid) which reduces friction from muscle movement.

MembranesMembranesSerous membranesSerous membranes:Basically they cover areas such as the

◦thoracic cavity (parietal pleura)◦ventral cavity (parietal peritoneum)◦organs of the cavities (visceral pleura and visceral peritoneum)

MembranesMembranesSerous membranesSerous membranes:

MembranesMembranesMucous membranesMucous membranes:are involved in absorption and secretion.

They line various body cavities that are exposed to the external environment and internal organs.

Examples are the nasal and oral cavities, tubes of the respiratory, digestive, urinary and reproductive tracts.

Mucous membranesMucous membranes:Usually found near or on glands that will help secrete a mucous. (Goblet cells secrete mucous)

Consist of epithelium overlying a layer of loose connective tissue.

MembranesMembranes

Synovial Synovial membranes: membranes: is the soft tissue that lines the non-cartilaginous surfaces within joints (synovial joints).

They secrete a fluid to lubricate the joints.

MembranesMembranes

Cutaneous membranes: Cutaneous membranes: commonly commonly called called The skin

They consist of stratified squamous epithelium and the underlying connective tissues.

Cutaneous membranes are thick, relatively waterproof, and dry.

The skin helps in regulating body temperature and maintaining homeostasis.

MembranesMembranes

MembranesMembranesCutaneous membranes:Cutaneous membranes:

THE SKIN – THE SKIN – INTEGUMENTARY SYSTEMINTEGUMENTARY SYSTEM

Layers of the skin and the accessory organs

Skin and its tissuesSkin and its tissues

One of the most versitile organs in the human body◦Maintains homeostasis◦Protects◦Regulates body temperature◦Retards water loss◦Houses sensory organs◦Synthesizes various biochemicals◦Excretes small amounts of wastes◦Plays a role in producing vitamin D

Dehydrocholesterol (either from diet or synthesized from the digestive system) coverts to Vit D in the presence of UV light

Layers of skinLayers of skin

Has two distinct layers:◦Epidermis◦Dermis◦Basement membrane separates the two

Beneath dermis is the subcutaneous (hypodermis) layer.

No sharp boundary is between the dermis and subcutaneous layer

EPIDERMISEPIDERMISThe outer layer

Composed of stratified squamousepithelium

Contains five separate layers: Stratum CorneumStratum Corneum- - outer most layer- mostly dead cells, produces keratin

Stratum lucidumStratum lucidum- only on the palms and soles, maybe missing where skin is thin, transparent in appearance as viewed by a microscope

Stratum Granulosum-Stratum Granulosum- a thin layer of cells, made up of migrating keratinocytes

Stratum Spinosum Stratum Spinosum – – found between the stratum found between the stratum granulosum and stratum basale; keratinization begins heregranulosum and stratum basale; keratinization begins here

Stratum Basale- Stratum Basale- The area where cells divide rapidly, nourished by dermal blood vessels

EPIDERMISEPIDERMIS

5 Layers of Epidermis:

Here is what happens to make these layers: ◦1. The basale layers divide rapidly pushing the cells and tissues up toward the top.

◦2. The closer they get to the top the less nutrients they have from the connective tissue so they eventually die (This becomes your Corneum layer)

EPIDERMISEPIDERMIS

The process of these cells hardening and dying is called KERATINIZATION

◦This is when they can secrete the protein Keratin to make the skin tough and water proof.

EPIDERMISEPIDERMIS

Your epidermis also contains MELANIN:MELANIN: is a dark pigment that provides your skin color. ◦Melanocytes are the cells that produce the melanin. They are found in the deep layers of the epidermis.

◦WHY Would you want them in the deep layers instead of the corneum?

EPIDERMISEPIDERMIS

HOW or why do you think people have different colors of skin then? DISCUSS with your table and come up with an answer!

EPIDERMISEPIDERMIS

EPIDERMISEPIDERMIS

Most people have the same number of melanocytes but the differences are due to the amount of melanin they produce.

It is genetic!!

If genes instruct the melanocytes to produce a lot of melanin then your skin is darker.

EpidermisEpidermis

How do you think sunlight plays a role in melanin and skin color? (Obviously sun UVA rays can make you darker- but why do you think so?) DISCUSS as a table and come up with an answer to report out.

EPIDERMSEPIDERMS

ANSWER: The sun stimulates (Speeds up) production of the melanin pigment.

DERMISDERMISKnown as the Inner layerVery thickContains: Connective tissues, epithelial

tissues, smooth muscle tissue, nervous tissue and blood vessels.

This is where your fingerprints come from. Supplies nutrients to the epidermis and

regulates body temperature.

Contains sensory receptors (touch receptors, temperature receptors- sweat glands, and so forth)

Also contains the HAIR FOLLICLES, NAILS SWEAT GLANDS, and SEBACACEOUS GLANDS

DERMISDERMIS

HAIR FOLLICLE:HAIR FOLLICLE: Hair is present everywhere except:

palms, soles, nipples, and some external reproductive parts.

Hair develops from a group of epidermal cells at the base of a hair follicule that divide and grow until they are pushed up and out and are dead.

DERMISDERMIS

SO HAIR IS DEAD- What type of dead cells do you think they are? DISCUSS and come up with an answer.

DERMISDERMIS

ANSWER: Once the cells get pushed up they become the keratinized dead epidermal cells.

Think back to what we talked about with Melanin and skin color. HOW do you think genetics and melanin determine hair color? DISCUSS as a group and come up with an answer.

DERMISDERMIS

Genes determine the type and amount of pigment the melanocyte cells will produce. So your hair follicles have melanocyte cells at the base of them.◦Brown-black hair has more eumelanin ◦Blonde hair has more pheomelanin ◦RED hair is the exception- they have a pigment

called: Trichosiderin. ◦Hair that is white is amelanistic.

When you get older how does your hair start to turn gray and then white?

DERMISDERMIS

ANSWER: The melanocyte cells eventually over time die and stop producing melanin.

Arrector Pili muscle: a smooth muscle attached to the hair follicle.

Causes your hair to “stand up” when you have the goosbumps- either emotional response or cold.

NAILSNAILS

Protective covering on the end of fingers and toesConsists of a nail plate and nail bedAre continuous with the epithelium of the skin –

produces the nail bedMoon-shaped region (lanula) is the whitish,

thickened at the base of the nail is the most actively growing region. ◦The cells divide and become keritinized. ◦Become part of the nail plate◦Keep pushing forward over the nail bed.◦The keratin here is thicker than keratin in the stratum

corneum◦In time the nail plate extends over the nail bed and wears

down with normal use.

DERMISDERMIS

Sebaceous Glands: Sebaceous Glands: associated with hair follicles. Secrete oil called sebum through small ducts into the hair.

Helps keep hair and skin soft and waterproof.

DERMISDERMIS

SWEAT GLANDS:SWEAT GLANDS: There are different types of sweat glands. ◦Eccrine glands: Eccrine glands: respond to a rise in temperature and are located on the forehead, neck and back where they produce droplets of sweat to cool the body down.

◦Apocrine glands: Apocrine glands: become active at puberty or when a person is emotionally upset. (arm pit region or groin).

Sweat Gland:

DERMISDERMIS

Sweat glands: sweat is more than just water- contains salts and other wastes.

Sweat glands help regulate body temperature.

SUBCUTANEOUS LAYERSUBCUTANEOUS LAYERBeneath the dermisConsists of Loose Connective tissue and

Adipose. Contains most of the blood vessels for

supplying the epidermis nutrientsAlso insulates- conserving body heat and

keeps too much heat from coming into the body.

THE THREE LAYERS:

THE SKIN: THE SKIN:

LABEL THE DIAGRAM: